Cut is not as expected
[Answer added for completeness.]
⎈ CtrlR initiates a loop cut and a new edge loop intersecting the chosen edge.
To cut through a number of edges, which are not connected by edge loops, use the Knife Tool.

Go to an orthographic view (front view).
Press K to enter the knife tool, press Z (to enter cut through mode) and C (to constrain the angle). Then draw a poly line with two  LMB clicks. Press ⏎ Enter to confirm.


The options you activate while the tool is selected.

Cut through Z
Allow the Cut tool to cut through to obscured faces, instead of only the visible ones.
Angle constrain C
Constrains the cut to 45 degree increments.